Device and method for dosing cryogenic liquid

ABSTRACT

Systems and methods of producing a frozen food product include dosing ingredients with a liquefied gas while mixing the ingredients using self-cleaning interlocking beaters. The beaters are optionally also disposed to clean a container in which the ingredients are frozen. The rate and amount of cooling is controlled by measuring the quantity of liquid nitrogen, measuring viscosity of the frozen food product, measuring temperature, and/or the like.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 13/243,978 entitled “Device and Method for MixingViscous Substances,” filed Sep. 23, 2011 which in turn claims priorityand benefit of U.S. provisional patent application Ser. No. 61/403,966filed Sep. 23, 2010 and entitled “Device and Method for Mixing ViscousSubstances,” and U.S. provisional patent application Ser. No. 61/404,127filed Sep. 27, 2010 and entitled “Device and Methods for DosingCryogenic Liquid;” and this application claims priority and benefit ofU.S. provisional patent application Ser. No. 61/952,092 entitled“Confectionary Manufacturing” and filed Mar. 12, 2014. The disclosuresof all the above patent applications are hereby incorporated herein byreference.

BACKGROUND

1. Field of the Invention

The invention is in the field of generating frozen mixtures, and in someembodiments in the field of ice cream manufacture.

2. Related Art

Ice cream, one of many frozen confections, is a well-known and favoritedesert of millions of people. It is commonly prepared by mixingingredients such as milk, dairy products, sugar, emulsifying agents,stabilizers, colorants and flavoring agents, sometimes in admixture withsolid ingredients that are to be dispersed through the final product,agitating the ingredients while they are chilled and then freezing themixture.

SUMMARY

Various embodiments of the invention include systems and methods ofcreating ice cream using a liquefied gas to rapidly cool theingredients. Rapid cooling produces desirable characteristics in icecream.

An exemplary embodiment includes a system for reproducibly providingdoses of liquid nitrogen to ice cream ingredients. The amount of liquidnitrogen provided can be controlled by pre-measuring a quantity ofliquid nitrogen, by measuring viscosity of the cooling ingredients,measuring the amount of cooling achieved, or any combination of theseapproaches.

Various embodiments of the invention include a system comprising acontainer mount configured to support a container, a first motorconfigured to rotate the container mount, a container configured to holdingredients and to temporally attached to the container mount, a liquidnitrogen dosing system configured to provide a controlled amount ofliquid nitrogen to the ingredients in the container such that theingredients freeze, and interlocking beaters configured to mix theingredients in the container and configured to be self-clearing to eachother, the interlocking beaters being disposed to pass within 1/16^(th)of an inch of each other without contacting each other, theself-cleaning being sufficient to remove the frozen ingredients from theinterlocking beaters.

Various embodiments of the invention include a method of making icecream, the method comprising: placing ingredients in a container; mixingthe ingredients using at least two interlocking beaters disposed suchthat the interlocking beaters are within ⅛^(th) of an inch of each otherbut do not touch each other; rotating the container in a directionopposite a rotation of a member of the beaters closest to a side of thecontainer; freezing the ingredients during the steps of mixing androtating by adding a controlled amount of a coolant to the ingredients,the coolant optionally includes a liquefied gas.

Various embodiments of the invention include a system comprising: acontainer configured to hold ingredients and to rotate; at least twointerlocking beaters configured to mix the ingredients in the containerand configured to be self-clearing from each other and to clean a sideand/or bottom surface of the container; a liquid nitrogen dosing systemconfigured to provide a controlled amount of cooling from a liquidnitrogen source to the ingredients; a temperature sensor configured tomeasure the controlled amount of cooling; and a controller configured toregulate the delivery of liquid nitrogen from the liquid nitrogen sourcein response to the measurement of the controlled amount of cooling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a general perspective view of an ice cream productiondevice, according to various embodiments of the invention.

FIG. 2 illustrates the interior components of the system illustrated inFIG. 1, according to various embodiment of the invention.

FIGS. 3A and 3B illustrate the interconnectivity of the beater andcontainer design, according to various embodiments of the invention.

FIG. 4 illustrates a control panel, according to various embodiments ofthe invention.

FIG. 5 illustrates a block diagram of the control panel illustrated inFIG. 4, according to various embodiments of the invention.

FIG. 6 illustrates a flow chart of an example algorithm for dispensingof liquid nitrogen, according to various embodiments of the invention.

FIG. 7 illustrates the beater drive system, according to variousembodiments of the invention.

FIGS. 8A-C illustrates helical beaters in a container, according tovarious embodiments of the invention,

FIG. 9 illustrates alternative beater/agitator designs, according tovarious embodiments of the invention.

FIG. 10 illustrates a method of making frozen ice cream, according tovarious embodiments of the invention.

FIG. 11 illustrates the ice cream production system of FIG. 1 furthercomprising a liquid nitrogen dosing system, according to variousembodiments of the invention.

FIG. 12 illustrates a cross-sectional view of a liquid nitrogen dosingsystem, according to various embodiments of the invention.

FIGS. 13A and 13B illustrate the embodiments of a liquid nitrogen dosingsystem illustrated in FIG. 12 at two steps in a dosing process,according to various embodiments of the invention.

FIG. 14 illustrates an embodiment of a lifting mechanism, according tovarious embodiments of the invention.

FIGS. 15A-15G illustrate alternative embodiments of a liquid nitrogendosing system.

FIG. 16 illustrates methods of making ice cream, according to variousembodiments of the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a mixer-like body with arm 1 a that attaches to mixerhead 1 b. Extending down from the mixer head are two or more beaters(e.g., agitators or mixing arms) 2. Beneath the beaters is a container3. The container clips or locks into place atop a container mount 4. Thecontainer mount is optionally heated and sits atop body 5. The mixerhead may or may not have supporting structure 6. The device may becontrolled by on/off switch or lever, or by a more detailed controlpanel 7. The wiring and components for the device may or may not haveprotected casings 8. The mixer arm 1 a is designed such that thecontainer can be removed and inserted under the beaters 2. In thisembodiment, the mixer arm can move from the production position (shown)to an upright position, wherein the head 20 tilts up and back.Additionally, the mixer head may or may not have handle 9, which can beused to move the mixer head to and from the production position. Inalternative embodiments the mixer up may move up or to the side to clearthe container 3.

FIG. 2 shows container mount 4 connected to a belt drive 10 and poweredwith a mount motor (or combination of transmission and motor) 15.Container 3 is optionally connected to container mount 4 by a spindle(not shown). The spindle can be concentric or non-concentric withcontainer 3. Beaters 2 are driven by transmission 11, which is connectedto motor 13 (also visible is shaft coupler 12). In this embodiment,mixer arm 1 a is raised using e.g. gas spring 14.

FIGS. 3A and 3B show one embodiment of the interconnectivity of thebeaters 2 and container design. Each beater 2 has a shaft 2 a and ahelical spiral 2 b. The beaters 2 are matched such that, when they arepaired together and inserted into the mixer head 1 b, the spirals fit 2b inside each other without touching the other spiral 2 b or the otherbeater 2 a shaft but within very close proximity of both. Specifically,the diameter of the spiral 2 b and center shaft 2 a as well as the wirediameter (i.e., thickness of the spiral) is such that the outer edge ofone beater's spiral almost comes into contact with the shaft of theother beater. In various embodiments this distance can be less than ¼,3/16^(th), ⅛^(th), or 1/16^(th) inches. In addition, the pitch,diameter, spacing and wire diameter is such that, at the centerintersection of the installed beaters 2, the high side of one spiral isdirectly under the low side of the other. Because the helical spirals 2b of the beaters 2 overlap and part of one of the helical spirals 2 b isalways close to part of the other of the helical spirals 2 b as theyturn, the beaters 2 are considered to be “interlocked.” As used herein,the term “interlocked beaters” is defined to include these features.Furthermore, the high side of one spiral 2 b is almost in contact withthe low side of the other at the front proximity point and the low sideof that same spiral is almost in contact with the high side of the otherat the rear proximity point (no actual contact but can be less than1/16^(th), ⅛^(th) or 3/16^(th) inch apart in various embodiments).Representative measurements are shown in FIGS. 3A and 3B. Thesemeasurements are for illustrative purposes only and are not meant to belimiting. This design is scalable vertically and scalable in size. Thereare many possible cross-sectional designs for the spirals, including,elliptical, rectangular, circular, etc.

In this embodiment of the beater and container design, the beaters 2,when installed into the mixer head, are sized to closely fit theinterior walls of the container 3, such that the outer edge of eachspiral is in very close proximity with the interior wall of thecontainer. For example, in various embodiments, separation betweenhelical spirals 2 b and the side of container 3 is less than 1/16^(th),⅛^(th) or 3/16^(th) inch. While this close fitting container 3 was foundto be the advantageous, a larger container 3 would also be possible, aslong as the diameter of the collective beaters 2 is longer than theradius of the container (See, for example, FIGS. 8A-C). Additionally, anoff-center container mount 4 could be used. Regardless, the taper of thehelical spirals 2 b should match that of the container 3—for example, ifthe helices do not taper, as shown in this variation, then the container3 is straight-sided and flat-bottomed, such that the bottom of thehelical spirals 2 b are able to be within very close proximity to theinterior bottom of the container 3.

A region 310 of helical spirals 2 b is optionally parallel to a bottomof container 3 and is optionally straight. Region 310 is at the part ofhelical spirals 2 b closest to the bottom. In various embodiments all ormost of Region 310 is less than 1/16^(th), ⅛^(th) or 3/16^(th) inch fromthe bottom of container 3. As such, in some embodiments, essentially allof the bottom is cleaned by the relative motion of container 3 andbeaters 2.

FIG. 4 shows an exemplary embodiment of a detailed control panel 7 whenthis embodiment is used for preparing a frozen product using liquidnitrogen—one of many potential applications of this invention. In thisexample, there is a freeze button 7 a (which could be removed if theembodiment was not used for frozen applications), a mix button 7 b, anda stop button 7 c. This example also includes a size knob 7 d, which canbe used to select various serving sizes (regular, large, pint, taste).This variation also includes a mixer Speed knob 7 e, which ranges fromslow to fast. This example also includes a viscosity knob 7 f, whichranges from soft to hard. The viscosity knob 7 f is configured tocontrol the viscosity of the final product, which may be determined bymeasuring actual viscosity or some other parameter as discussedelsewhere herein. The interior of this variation of control panel couldinclude a printed circuit board with wiring connections. Mixer Speedknob 7 e can be configured to control the speed of beaters 2 and/orcontainer mount 4. In addition to viscosity selection, control inputsmay be configured for a user to select between various recipes as someingredient combinations and/or products require greater or lessercooling than others. The different recipes may include differentingredient ratios and/or different total quantities of ingredients. Forexample, an input may be configured for selection between small, mediumand large quantities (sizes) of product.

FIG. 5 shows an example of a block diagram of a control circuit 510 andother components of the system associated with the control panel 7 shownin FIG. 4. Wiring from control circuit 510 connects to variouscomponents of the device, including to the panel controls 580, mountmotor 15 and beater motor 13. For example, Control Circuit 510 may beconnected to one or more valves 560 configured to control the flow ofliquid nitrogen from a Dewar 550 to a Nozzle 570. Nozzle is typicallydisposed adjacent to container 3 such that the liquid nitrogen thatflows from the nozzle reaches the ice cream ingredients. Valve 560 isoptionally replaced by a scoop or other device configured for sampling acontrolled amount of liquid nitrogen. Control Circuit 510 is optionallyconnected to a level sensor within Dewar 550. Beater Motor 13 isconfigured to rotate beaters 2. Mount motor 15 is configured to rotatecontainer mount 4.

Sensor 520 is configured to detect properties of the frozen ingredientsduring the freezing process. In some embodiments, sensor 520 isconfigured to detect a viscosity of the ingredients. For example, sensor520 may be configured to detect a load on beater motor 13 or mount motor15. In this case sensor 520 can include strain, current or voltagesensor configured to detect the torque or power needed to drive themotor 13 or mount motor 15. In some embodiments, sensor 520 includes atemperature measurement device, such as a thermocouple. The thermocouplecan be connected to beaters 2, container 3, and/or nozzle 570. Invarious embodiments the thermocouple is disposed in the stream of liquidnitrogen as it leaves nozzle 570, to measure the temperature of theoutput pipe 1125, and/or to measure the temperature of the ingredientsas they are being mixed and cooled. In addition to the thermocouple,sensor 520 can include a metallic or non-metallic probe (e.g., a copperplate) whose temperature is changed by the liquid nitrogen and ismeasured by the thermocouple. Some embodiments include more than onesensor 520. The output of sensor 520 is optionally processed usingcircuits and/or computing instructions executed within control circuit510, to perform various functions described herein.

One or more viscous substances is/are placed in container 3. Forexample, if the method is being used to make a frozen dessert, suchingredients may include unfrozen ice cream or custard mix, or pureedfruit for sorbet, or yogurt, or milk or cream, or a non-dairy substitutefor milk or cream. Additional ingredients/accompaniments/toppings (e.g.,in the case of a frozen dessert: cookies, fresh fruit, or nuts) may alsobe added to the container prior to or during the process of mixing (and,in this case, freezing). Substance/ingredients may either be placed intothe container before or after the container is placed on the containermount.

When the Mix button 7 b on control panel 7 b is pressed, beatertransmission 11, driven by its accompanying motor 13, rotates thebeaters, with each beater rotating in the same direction and speed ofrotation as the other beater. In some embodiments, the spirals of thebeaters move in a downward direction such that the spiral helices 2 bare pushing the substance/ingredients downward into the container. Atthe same time, belt drive 10 powered by its accompanying gear-motor 15rotates the container 3 at an asynchronous speed relative to thebeaters. In some embodiments, the container 3 rotates (typically but notnecessarily in the opposite direction as the collective beaters 2 andturns at such a speed with non-small integer ratios such thatessentially all of the container's side is scraped by the beaters(again, the beaters 2 not quite touching the side of container 3. Inother embodiments the container 3 does is fixed and does not rotate. Inthese embodiments motor 15 and the associated drive system elements areoptional. To demonstrate the rotating container embodiment, in FIG. 3A,spiral helices 2 b move counter-clockwise, while container 3 movesclockwise. Due to the beaters' helical shape and movement, in practice,the beaters 2 act to scrape the ingredients from each other's surfaceand to propel the ingredients down into the container. The ability toremove frozen ingredients from each other makes the beaters 2 jointlyself-cleaning. Additionally, because the beaters 2 are designed to fitthe container 3 and the container 3 is rotating at an asynchronous speedrelative to the collection of beaters 2, the beaters 2 also act toscrape the ingredients off of the sides of the container 3. Due to theasynchronous movement between the collective beaters 2 and the container3, the collective beaters 2 are, in essence, orbiting together aroundthe interior surface of the container 3, such that most interior sidesof the container are scraped by the collective beaters 2. If pitch,diameter, spacing and wiring gauge are all correct, most of the surfacesare close to a scraping action.

The underlying purpose of this beater-container design is to ensure thatthe substance in the container is evenly mixed (and, in the case ofmaking a frozen product, frozen) throughout and that all ingredients areincorporated into the mixing (and, in the case of making a frozenproduct, freezing) process. Additionally, the collective helical beaterdesign minimizes crushing of additive by allowing their escape frombetween moving parts, using a wiping rather than a crushing motion atintersections. This beater-container design is especially effective formaking frozen product using liquid nitrogen as the freezing agentbecause the formation of small ice crystals has a significant impact onthe texture of the frozen product (e.g., ice cream). Some embodiments ofthe invention ensure the creation of an exceptionally high qualityfrozen novelty product—the formation of exceptionally small icecrystals—because of the even distribution of the ingredients, theconstant scraping of ingredients off surfaces, and the downward motionof the spirals. Note that in some embodiments the container 3 is movedwhile the beater(s) 2 is (are) stationary.

The control circuit 510 can be programmed to run the motors for a numberof seconds every time the mix button is pressed and then to stop runningthe motors after that time is up. Alternatively, the control circuit 510can be programmed to run the motors continuously, in which case Stopbutton 7 c can be pressed to halt the motors. There may or may not be amixer speed knob 7 e, which moves the beaters 2 and/or the container 3faster and slower depending on its position. Additionally, if desired,the control circuit 510 can be programmed to read Size knob 7 d (suchthat the device mixes for a longer time depending on the amount ofingredients placed in the container); Viscosity knob 7 f (such that thedevice mixes until the desired viscosity has been reached), and/or arecipe knob (not shown) to select between different recipes. The knobinputs illustrated in may be replaced by digital inputs such as acomputer touchscreen interface, membrane switches, a graphical userinterface, and/or the like.

Embodiments may or may not have viscosity measurement capabilities, i.e.the viscosity knob 7 f on the control panel 7. When this capability isincluded, the entire device can be integrated and the entire mixing(and, in the case of making a frozen product, freezing) process can becompletely automated, without requiring the watchful eye of a machineoperator. For example, in some embodiments, control circuit 510 isprogrammed to read the torque of either the beater motor or thecontainer motor and control the dosing of coolant depending on themeasured torque and the viscosity knob 7 f setting. Generally, thebeater torque has a lot of noise in it, so in one approach is to use themeasurement of the container motor torque and to use a small motor,which can give a good indicator of how viscous the substance is. Becausethe collective beaters optionally have asynchronous movement relative tothe container, the motors driving the container and beaters are, inessence, working against each other to some degree. For instance, in theaforementioned example, the container is moving in the oppositedirection as the collective beaters such that the collective beaters areworking “against” the container. As such, when the substance oringredients is/are thickening, the motors have to work harder andharder. By setting the desired viscosity, the operator is indicating howhard the motor should work before stopping and, in essence, before thesubstance/product is done and ready for removal from the container (orready for the next step in its mixing process). The control circuit 510can be programmed to take into account momentary increases in torque asa result of the beaters working through chunks (e.g., in the case ofmaking a frozen dessert, these chunks may be nuts or chocolate chips).For instance, logic on control circuit 510 can be set to shut down thesystem (and stop coolant introduction) when the system exceeds a certaintorque for a number of seconds in a row. As such, momentary increases intorque are ignored. This logic can include hardware, firmware and/orsoftware stored on a computer readable medium.

In the case of making a frozen product using liquid nitrogen, liquidnitrogen can either be added manually or through a dosing system, whichwould typically be connected to a liquid nitrogen supply—an example ofthis supply is shown as Dewar 550 in FIG. 5. If the liquid nitrogen isadded manually, then the freeze button 7 a on control panel 7 acts thesame as mix button 7 b. In this case, there need only be one button orlever, in essence Mix/Freeze, which activates the device. Note that themix button 7 b is optional. Mixing can occur manually outside of thecontainer 3.

If the device is hooked up directly to a liquid nitrogen supply andaccompanying dosing system, then the freeze button 7 a in FIG. 4optionally has additional functionality. For example, the freeze button7 a may cause control circuit 510 to start and stop the dispensing ofthe liquid nitrogen into the container 3. In essence, the controlcircuit 510 can have a connection point to the dosing system such thatthe freeze button 7 a activates some sort of valve (e.g., valve 560,depending on the selected dosing system), such as a needle valve or asolenoid valve, which releases liquid nitrogen into the container 3. Thecontrol circuit 510 may also have a connection point for a level sensor,which would ensure that the liquid nitrogen supply is sufficient. Thedosing system may also have a phase separator such that a known quantityof liquid can be added. The software associated with the Freeze buttoncan be programmed to have different liquid nitrogen dispensingalgorithms for different sizes or variations of frozen novelty products.An example algorithm is shown in FIG. 6. In this variation, Size knob 7d can be used to select which liquid nitrogen dispensing algorithm isused. For instance, a large size requires more liquid nitrogen dispensedthan a regular size. The algorithms may be based on a combination of thefollowing factors: quantity of liquid nitrogen, time, output of sensor520 (a viscosity or temperature measurement), and torque/load of themotor(s). The liquid nitrogen, when added manually or through theintegrated dosing system, can be added in one bulk pouring or inmultiple releases over a period of time. Typical dispensing times areunder two minutes for a 4-10 ounce batch size.

FIG. 6 illustrates several methods that may be performed using controlcircuit 510. These include a) determining at regular intervals if moreor less liquid nitrogen should be added and turning on or off valve 560accordingly; b) monitoring an amount of cooling that has been providedto the ingredients and turning on or off valve 560 accordingly; c)detecting which of panel controls 580 have been activated; starting andstopping motors 13 and/or 15; and monitoring viscosity of the frozeningredients and turning on or off valve 560 accordingly.

FIG. 7 shows the beater drive system, according to various embodimentsof the invention. The beater drive system includes a beater motor 13,mechanically coupled to transmission 11 and drive shafts 2 a configuredto turn the beaters 2. The beater motor 13 optionally includes sensor520 configured to measure motor speed or current drawn by one or more ofthe motors 13 or 15. The beater drive system typically includes a hinge740 configured such that the beaters 2 can be lifted from the container3. Hinge 740 is optionally motorized and controlled by control circuit510. In alternative embodiments, the same motor is configured to rotateany combination of beaters 2, hinge 740, and/or container 3. The beaterdrive system is optionally configured to rotate beaters in the samedirection, and optionally configured to rotate at least one of beaters 2in a direction opposite the rotation of container 3. Beater motor 13 isoptionally disposed in alternative positions.

FIGS. 8A and 8B show examples of helical beaters 2 in a container 3,according to various embodiments of the invention, in these examples thehelical beaters 2 are disposed such that one of the beaters 2 is closerto a side surface 810 of the container 3 relative to a second of thebeaters 2. In various embodiments the distance between the closer beater2 and side surface 810 is less than ¼, 3/16^(th), ⅛^(th), or 1/16^(th).However, in typically embodiments the closer beater is disposed suchthat it does not touch side surface 810. Similar positioning betweenside surface 810 and beaters may be found in embodiments wherein beaters2 are symmetrically disposed within container 3. Either of thesepositions allows beaters 2 to clean frozen product from side surface810. If the beaters 2 rotate in opposite directions, then that beaterclosest to side surface 810 is rotated in a direction counter to sidesurface 810. Otherwise, the rotations are such that at least one ofbeaters 2 is disposed next to side surface 810 and rotates in adirection opposite to the direction side surface 810 is rotated.

FIG. 8C illustrates one example of a top view of beaters 2 and container3. The distances are shown in inches and degrees, and are meant to benon-limiting examples.

FIG. 9 illustrates various alternative beater 2/agitator designs,according to various embodiments of the invention. One feature common tomost of these designs is that they are self-cleaning. In each examplethe beaters 2 rotate so as to remove frozen product from each otherand/or from surfaces of the container 3.

FIG. 10 illustrates a method of making frozen ice cream, according tovarious embodiments of the invention. In an add ingredients step 1010ice cream ingredients are added to container 3. As described herein theingredients can include a wide variety of food stuffs including cream,yogurt, sugar, flavoring, and the like. The addition is optionallyautomated.

In a mix step 1020 the ingredients are mixed using two or moreinterlocking beaters 2. In various embodiments, the beaters 2 aredisposed to within less than ¼, 3/16^(th), ⅛^(th), or 1/16^(th) inchesof each other. Typically the beaters 2 do not touch each other. At thesedistances the beaters operate to be self-cleaning, e.g., they cleanfrozen (ice cream) product from each other. Mixing occurs by rotatingthe interlocking beaters 2.

In an optional rotate step 1030, the container 3 is rotated. Typicallythis rotation occurs in a direction that is opposite the rotationaldirection of a member of the beaters 2 that is in close proximity to aside of the container. For example, the member of the beaters 2 that isclosest to a side surface of the container. The container 3 can berotated using the same or a different motor than is used to rotate thebeaters 2.

In a freezing step 1040, a coolant is added to the ingredients in thecontainer 3. The coolant is typically a liquefied gas such as liquidnitrogen, and is delivered in a control manner. For example, in someembodiment a controlled amount (volume or mass) of coolant is added. Insome embodiments, the coolant is added for a specific length of time,until a measured viscosity of the ingredients is achieved, and/or untila desired temperature drop is achieved. Control can be achieved byopening and closing a valve or by collecting a specific amount of fluidfrom a reservoir.

The freezing step 1040 is optionally performed in parallel with ameasure viscosity step 1050. In measure viscosity step 1050 theviscosity of the ingredients is measured using sensor 520 as the coolantis added. As discussed elsewhere herein, viscosity can be measured bymonitoring current consumed by the motor 13 or 15, monitoring the speedof motor 13 or 15, and/or the like. If the viscosity is measured, thenthe delivery of the coolant to the ingredients can be controlledresponsive to this measurement.

The freezing step 1040 is optionally performed in parallel with ameasure temperature step 1060. In measure temperature step 1060 thetemperature of the ingredients is measured using and embodiment ofsensor 520 as the coolant is added. These embodiments of sensor 520 caninclude, for example, a thermocouple or an optical sensor. The measuredtemperature could be that of the ingredients themselves, part of beaters2, part of container 3, part of a nozzle used to deliver the coolant, orof a metallic (or non-metallic) object placed in the stream of thecoolant. If the temperature is measured then the delivery of the coolantto the ingredients can be controlled responsive to this measurement.Optionally, both temperature and viscosity are measured using separateembodiments of sensor 520.

FIG. 11 illustrates the ice cream production system of FIG. 1 furthercomprising a liquid nitrogen dosing system 1110, according to variousembodiments of the invention. The liquid nitrogen dosing system 1110 isoptionally controlled via control panel 7 and/or Control Circuit 510,and is configured to provide reproducible doses of liquid nitrogen oranother cryogenic liquid to container 3 via an output pipe 1125. Theliquid nitrogen dosing system 1110 may be manually filled or may beconnected to a pressurized reservoir (not shown) of liquid nitrogen. Inorder to provide reproducible doses of liquid nitrogen, liquid nitrogendosing system 1110 is configured to store a volume of liquid nitrogenand to release one or more dose of the liquid nitrogen to container 3from a bottom of liquid nitrogen dosing system 1110. The dose isreproducible, in part, because by sampling from the bottom the doseincludes primarily liquid rather than gas phase nitrogen. Liquidnitrogen dosing system 1110 optionally includes embodiments of Nozzle570, Valve 560 and Dewar 550. Liquid nitrogen dosing system 1110optionally includes a cover 1115 and a support structure 1120.

FIG. 12 illustrates a cross-sectional view of liquid nitrogen dosingsystem 1110, according to various embodiments of the invention. Theliquid nitrogen dosing system 1110 includes a container with vacuumjacketed walls 1205 and an optional relief vent 1220. An actuator 1210is connected to a lifting mechanism 1215 (e.g. a cam or lever arm). Theactuator 1210 can be manually actuated, or can be connected to a controlsystem (e.g., a button or switch) that is configured to run the liftingmechanism 1215 through one or more cycles of lifting, or can beconnected to a more complex control system such as control circuit 510and/or control panel 7.

Extending from the lifting mechanism 1215 is a wire or other connector1280 that attaches to a dipper mechanism 1265 a. One side of the dippermechanism 1265 a, referred to as the “head” of the dipper mechanism,extends down into a reservoir 1285 of cryogenic liquid. The head of thedipper mechanism has a scoop 1265 b of a desired size such that, whenthe dipper mechanism 1265 a is raised by the lifting mechanism 1215, acontrolled quantity of cryogenic liquid is transported to a deliveryport or funnel 1275. The delivery port or funnel 1275 is attached to theinterior of the liquid nitrogen dosing system 1110. The top of thedelivery port or funnel 1275 is disposed above a bottom of reservoir1285 such that it is above a normal operational liquid level 1290 ofcryogenic liquid. The delivery port or funnel 1275 is funnel or tubeconnected to output pipe 1125 such that liquid nitrogen introduced intothe funnel 1275 flows by action of gravity to container 3.

Typically, the interior of liquid nitrogen dosing system 1110 is at ornear atmospheric pressure. As such, the flow is liquid nitrogen intocontainer 3 is gravity fed and any excess pressure within liquidnitrogen dosing system 1110 does not cause significant variation in thevolume of liquid nitrogen provided per dose. Note that when not filledwith liquid nitrogen, delivery port or funnel 1275 is typically open toboth the atmosphere (adjacent to container 3) and the volume withinliquid nitrogen dosing system 1110 that contains gas phase (evaporated)nitrogen. As a result, the evaporation of liquid phase nitrogen withinliquid nitrogen dosing system 1110 causes a net flow of cold nitrogengas out through funnel 1275 and output pipe 1125. This results inprecooling and/or purging of output pipe 1125, prior to delivery ofliquid doses of nitrogen.

Liquid nitrogen dosing system 1110 may be filled with liquid nitrogen(and the liquid level 1290 approximately maintained) either manually orautomatically. In those embodiments that include automatic filling,liquid nitrogen dosing system 1110 includes a sensor 1260 configured todetect the level or quantity of liquid nitrogen in liquid nitrogendosing system 1110. In some embodiments, the sensor 1260 includes afloat level sensor that extends down from the top of liquid nitrogendosing system 1110.

However, in alternative embodiments, sensor 1265 includes a mass sensoror scale or other mechanism configured to measure a changing quantity ofcryogenic liquid within the liquid nitrogen dosing system 1110. Sensor1265 can be mechanical or electronic. In either case, sensor 1265 isconfigured to control an actuating valve 1225.

In embodiments including an electronic sensor 1265, sensor 1265 isconfigured to communicate an electronic signal via wiring, such asControl circuit 510, to actuation valve 1225.

The actuating valve 1225 is typically coupled to a cryogenic liquiddelivery pipe 1250 external to the vacuum jacketed walls 1205. Deliverypipe 1250 is configured to transfer liquid nitrogen from an external(liquid nitrogen) supply tank (not shown). The delivery pipe 1250 andthe external supply tank are optionally pressurized such that whenactuating valve 1225 is open liquid nitrogen flows into liquid nitrogendosing system 1110. Optionally, a diffuser 1245 is used to minimize thesplash of the cryogenic liquid as it enters the reservoir 1285. Thediffuser 1245 may be attached at an end 1240 of the delivery pipe 1250that is inserted into the container. The cryogenic liquid collects inthe reservoir 1285.

Control circuit 510 is optionally configured to control actuator 1210and actuating valve 1225. This control can be in response to apredetermined dosing algorithm, to a batch size, to a desired viscosity,to a temperature measurement, to an identity of the ingredients beingmixed, and/or the like.

If a sensing mechanism 1260 is used, then the sensing mechanism 1260senses the increased quantity of cryogenic liquid within reservoir 1285.The sensing mechanism 1260 can produce a signal that indicates thereservoir 1285 is at capacity and/or that the reservoir 1285 requiresmore cryogenic liquid in order to provide repeatable doses of cryogenicliquid. A computerized control system (e.g., Control Circuit 510) can beused to take the signal from the sensing mechanism 1260, interpret thissignal, and then send a signal to close or shut-off the actuating valve1225 when the reservoir 1285 reaches the maximum desired quantity ofcryogenic liquid. Whenever the sensing mechanism 1260 indicates to thecontrol system that the liquid level 1290 within reservoir 1285 ofcryogenic liquid has slipped below its minimum level, the control systemopens the actuating valve 1225 to fill the reservoir 1285 again, untilthe desired quantity of cryogenic liquid is reached. In the case of theembodiment shown in FIG. 12, the desired liquid level 1290 is in therange wherein the liquid level 1290 is beneath the opening of thedelivery funnel 1275 but above the level of the scoop in the head of thedipper mechanism 1265 b.

The components of liquid nitrogen dosing system 1110 illustrated in FIG.12 optionally have a protective covering 1115. Similarly, wiring for theactuating valve 1225 and/or wiring for the actuator 1210 that moves thelifting mechanism 1215, and the cryogenic liquid delivery pipe 1250 (ifpresent) may be encased in another pipe/covering 1120 such that the unitis smooth and cleanable from the outside.

To dispense cryogenic liquid from the container, the actuator 1210(which is actuated manually, or by a simple control switch/lever/system,or by a more complex/computerized control system) activates the liftingmechanism 1215. The lifting mechanism 1215 pulls the wire/connector1280, which raises the dipper head 1265 b. The cryogenic liquid that hascollected in the scoop of the dipper head 1265 b is then dispensed intothe delivery funnel 1275. The scoop/dose of cryogenic liquid then exitsthe container through the output pipe 1125. This invention isscalable—i.e., the container, the dipper mechanism, the scoop in thedipper head 1265 b, the delivery funnel 1275, etc. can be built towhatever size is preferable for the application.

FIGS. 13A and 13B illustrate the embodiments of liquid nitrogen dosingsystem 1110 illustrated in FIG. 12 at two steps in a dosing process.FIG. 13A shows a stream 1310 of cryogenic liquid (e.g. liquid nitrogen)coming through the diffuser 1245, as controlled by actuating valve 1225.As a result of liquid entering the container, the sensing mechanism1260, which in this case is a float level sensor, senses that the levelof cryogenic liquid in the reservoir 1285 has gone up. FIG. 13B showsthe dipper mechanism 1265 b being lifted up and above the liquid level1290 by the wire/connector 1280 being pulled by the lifting mechanism1215. As a result of the dipper mechanism 1265 b transfers a portion ofcryogenic liquid from the reservoir to the funnel 1275. The sensingmechanism 1260 senses a resulting drop in the liquid level 1290. If thedrop is sufficient, then further cryogenic liquid is added to liquidnitrogen dosing system 1110 as illustrated in FIG. 13A.

FIG. 14 illustrates an embodiment of the lifting mechanism 1215, whichincludes a lever arm 1410. The lever arm 1410 is connected to actuator1210. When actuated, the lever arm 1410 pulls up the wire/connector1280, which lifts the dipper mechanism 1265 a. The lifting of the dippermechanism 1286 a results in the transport of a dose of cryogenic liquidfrom the reservoir to the delivery funnel 1275. The interior of dippermechanism 1265 a is optionally hollow, such that, when the dippermechanism 1265 a pivots, cryogenic liquid can flow from scoop in thedipper head 1265 b through the dipper “tail” and into the deliveryfunnel 1275.

FIGS. 15A-H illustrate alternative embodiments of liquid nitrogen dosingsystem 1110 including different structures for delivering cryogenicliquid from the bottom of liquid nitrogen dosing system 1110. In some ofthe illustrated embodiments actuating valve 1225 is above the cryogenicliquid to minimize heat transfer and allow for easier cleaning. Notethat liquid nitrogen introduction elements such as sensor 1260 andactuating valve 1225 are not shown in these figures for clarity.

In the embodiments illustrated by FIG. 15A a cup 1510 of cryogenicliquid is emptied into funnel 1275 by being raised up and down. Thefunnel 1275 optionally includes holes 1515 through which the cryogenicliquid can flow. A seal 1520 is optionally used to close an openingbetween the cup 1510 and funnel 1275.

In the embodiments illustrated by FIG. 15B a hollow valve shaft 1525 isused to control flow of cryogenic liquid into funnel 1275. The hollowvalve shaft 1525 is configured to allow gas evaporated from thecryogenic liquid to enter the funnel 1275 when the valve is closed. Thiskeeps the interior of the system at near atmospheric pressure and canalso serve to purge and/or precool output pipe 1125. A spring 1528 isconfigured to hold the hollow valve shaft 1525 down (closed to liquidbut open to gas) in a default position. The hollow valve shaft 1525rests in a seal 1532 at the bottom of liquid nitrogen dosing system1110. The hollow valve shaft 1525 is optionally open at both ends suchthat gas can vent in both directions. The valve is opened to liquid flowby activation of a solenoid 1530 connected to the hollow valve shaft1525.

FIG. 15C illustrates an embodiment including two valves 1535 a and 1535b on a single shaft 1538. When shaft 1538 is lowered valve 1535 a isopened and valve 1535 b is closed. This allows a controlled volume ofcryogenic liquid to flow into a container 1540. The container 1540 isvented to the atmosphere and thus near atmospheric pressure. When theshaft 1538 is raised valve 1538 a is closed and valve 1535 b is opened.This allows the controlled volume to flow into funnel 1275 under theforce of gravity.

FIG. 15D illustrates an embodiment including two different valves 1538 aand 1538 b. When valve 1538 b is closed, valve 1538 a is opened allowingcryogenic liquid to fill container 1540. The opening and closing ofvalve 1538 b is controlled by a trigger 1543 coupled to the shaft ofvalve 1538 a. Valve 1538 b is opened by raising shaft 1525, for exampleusing lifting mechanism 1215. Opening valve 1538 b allows the cryogenicliquid to flow of container 1540 to funnel 1275, and also closes valve1538 a.

FIG. 15E illustrates embodiments in which the interior of liquidnitrogen dosing system 1110 is maintained at above atmospheric pressure,and this pressure facilitates flow of cryogenic cooling liquid throughoutput pipe 1125 to container 3. These embodiments include a pressurerelief valve 1544 configured to maintain a steady pressure within theinterior of liquid nitrogen dosing system 1110. Because this pressure ismaintained, the flow of cryogenic cooling liquid to funnel 1275 whenvalve 1538 b is opened is reproducible. In various embodiments pressurerelief valve 1544 is configured to maintain pressures of less than orequal to 5, 10 or 15 psi above atmospheric pressure. In some embodimentspressure relief valve 1544 is adjustable. Gas released from pressurerelief valve 1544 is optionally routed to outlet pipe 1125 for coolingand/or purging.

FIG. 15F illustrates embodiments which cup 1510 is filled tooverflowing. As a result when valve 1538 b is opened a volume ofcryogenic liquid equal to the volume of cup 1510 is transferred tooutput pipe 1125. All or part of this volume can be provided in asequence of doses by opening and closing valve 1538 b. Because the cupis at approximately atmospheric pressure and the flow is gravity fed,the volume of each dose is proportional to a length of time valve 1538 bis open. Cup 1510 is filled using a pump 1545 such as the piston pumpillustrated in FIG. 15F. The delivery of additional cryogenic liquidinto cup 1510 is avoided when the cup 1510 is being emptied.

FIG. 15G illustrates embodiments including an actuating valve 1225disposed within the interior of liquid nitrogen dosing system 1110, e.g.within reservoir 1285. Having actuating valve 1225 inside and exposed tothe vapor of the liquid nitrogen reduces warming and boiling of thecryogenic liquid as the liquid passes though the valve. Actuating valve1225 is opened and closed using a solenoid 1550. In the embodimentsillustrated valve 1538 a, configured to release cryogenic liquid tooutlet pipe 1125, includes the structures illustrated in FIG. 15B.However, other embodiments of valve 1538 a discussed herein may be usedin combination with the actuating valve 1225 illustrated in FIG. 15G.Solenoid 1550, and the other solenoids illustrated herein, optionallyincludes a bellows to separate electronic components of solenoid 1550from the cryogenic liquid and vapor thereof.

FIG. 16 illustrates methods of making ice cream, according to variousembodiments of the invention. These methods are optionally performedusing the embodiments illustrated by FIG. 11, and are optionallyperformed at part of the methods illustrated in FIG. 10. Add ingredientsstep 1010, in which placing ingredients in container 3, is discussedelsewhere herein. Mix step 1020 is also discussed elsewhere herein. InMix step 1020 the ingredients are mixed using one or more beaters 2disposed within the container 3.

In a sense level step 1610, a level of liquid nitrogen or anothercryogenic liquid within a liquid nitrogen dosing system 1110 is sensedusing level sensor 1260.

In an add liquid step 1620, liquid nitrogen or other cryogenic liquid isadded to the liquid nitrogen dosing system 1110 from a pressurizedliquid supply. The addition is optionally controlled by actuating valve1225 and responsive to the level sensor 1260.

In a store liquid step 1630 the liquid nitrogen or other cryogenicliquid is stored in the reservoir 1285 of liquid nitrogen dosing system1110. This storage may be at approximately atmospheric pressure or at acontrolled pressure. The pressure is optionally controlled by a reliefvalve 1544.

In an optional precooling step 1640, output pipe 1125 is precooled. Thisis optionally accomplished using a gas of the liquid nitrogen or othercryogenic liquid stored in the liquid nitrogen dosing system 1110.Precooling step 1640 may be a continuous process in which the gas flowsthrough output pipe 1125 to both cool and purge.

Rotate Step 1030, is discussed elsewhere herein, and includes rotatingcontainer 3 and/or one or more of beaters 2.

Dispense step 1650 includes dispensing the added liquid nitrogen fromthe liquid nitrogen dosing system 1110 into the container 3 in acontrolled amount. Dispense step 1650 can occur during Mix Step 1020,Rotate Step 1030, freeze step 1040, measure viscosity step 1050, and/ormeasure temperature step 1060, for example. Dispense step 1650 typicallyresults in cooling and/or freezing of the ingredients. Dispense step1650 optionally occurs in one or more doses as controlled by controlcircuit 510. The liquid dispensed in dispense step 1650 has beenseparated from the vapor of this liquid. This greatly improves the massand volumetric precision of each dose. As discussed elsewhere herein,the amount of cryogenic liquid dispensed in dispense step 1650 isoptionally responsive to viscosity measurement, recipe, temperature,etc.

Measure Viscosity Step 1050 and Measure Temperature Step 1060 arediscussed elsewhere herein.

Several embodiments are specifically illustrated and/or describedherein. However, it will be appreciated that modifications andvariations are covered by the above teachings and within the scope ofthe appended claims without departing from the spirit and intended scopethereof. For example, while ice cream is discussed herein, alternativeembodiments of the invention may be applied to frozen yogurt or otherfrozen foods. In some embodiments one of the interlocking beaters isheld stationary while the other is rotated. The use of gravity fedcryogenic liquids to freeze ingredients of frozen food products enablesmore reproducible dosing of liquid coolants, and thus a morereproducible product, relative to systems in which cryogenic liquids areprovided at unpredictable pressures.

The embodiments discussed herein are illustrative of the presentinvention. As these embodiments of the present invention are describedwith reference to illustrations, various modifications or adaptations ofthe methods and or specific structures described may become apparent tothose skilled in the art. All such modifications, adaptations, orvariations that rely upon the teachings of the present invention, andthrough which these teachings have advanced the art, are considered tobe within the spirit and scope of the present invention. Hence, thesedescriptions and drawings should not be considered in a limiting sense,as it is understood that the present invention is in no way limited toonly the embodiments illustrated.

The invention claimed is:
 1. A system comprising: a container mount; acontainer configured to hold ingredients and to be attached to thecontainer mount; a liquid nitrogen dosing system configured to provide acontrolled amount of liquid nitrogen to the ingredients in the containersuch that the ingredients become frozen, the provision of the controlledamount of liquid nitrogen to the ingredients in the container beinggravity fed, the liquid nitrogen dosing system including a valveconfigured to control flow of liquid nitrogen from a pressurized sourceinto the dosing system and including a liquid level sensing mechanismconfigured to measure a level of liquid nitrogen within the dosingsystem; and one or more beaters configured to mix the ingredients in thecontainer during delivery of the liquid nitrogen from the dosing system,the beaters being driven by a first motor.
 2. The system of claim 1,further comprising a second motor configured to rotate the containermount.
 3. The system of claim 1, further comprising a temperature sensorconfigured to measure a cooling of the ingredients, a cooling of anoutput pipe or cooling of the container.
 4. The system of claim 3,further comprising a circuit configured to control the dosing system inresponse to the temperature sensor.
 5. The system of claim 1, furthercomprising a sensor configured to measure a viscosity of theingredients.
 6. The system of claim 5, further comprising a controlcircuit configured to control the one or more beaters in response to thesensor.
 7. The system of claim 6, wherein the circuit includes an inputconfigured for a user to select a recipe, quantity or viscosity of thefrozen ingredients and to control the dosing system in response to theselection.
 8. The system of claim 6, further comprising an armconfigured to move the beaters in and out of the container, the controlcircuit being configured to further control the beaters in response to aposition of the arm.
 9. The system of claim 1, further comprisingcontrol circuit configured to control provision of liquid nitrogen fromliquid nitrogen dosing system to the container.
 10. The system of claim9, wherein control circuit is configured to control the provision ofliquid nitrogen from liquid nitrogen dosing system to the containerresponsive to a torque or current sensor.
 11. The system of claim 9,wherein control circuit is configured to control the provision of liquidnitrogen from the liquid nitrogen dosing system to the containerresponsive to a stored dosing algorithm comprising a series of liquidnitrogen releases.
 12. The system of claim 1, wherein the liquidnitrogen dosing system further comprises an output pipe configured forthe liquid nitrogen to pass through to the container and the liquidnitrogen dosing system is further configured to precool the output pipeusing nitrogen gas.
 13. The system of claim 1, further comprising an armconfigured to move the beaters in and out of the container and toposition the beaters within less than ⅛^(th) of an inch of a side of thecontainer.
 14. The system of claim 1, wherein the liquid level sensingmechanism is further configured to control flow of pressurized liquidnitrogen into the liquid nitrogen dosing system so as to maintain thelevel of liquid nitrogen within the dosing system.
 15. The system ofclaim 1, wherein the liquid nitrogen dosing system is configured tostore the liquid nitrogen within the dosing system at atmosphericpressure.
 16. A method of making ice cream, the method comprising:placing ingredients in a container; mixing the ingredients using one ormore beaters disposed within the container; sensing a level of liquidnitrogen within a liquid nitrogen dosing system, using a level sensor;adding liquid nitrogen to the liquid nitrogen dosing system from apressurized liquid nitrogen supply, the addition being controlled by avalve responsive to the level sensor within the liquid nitrogen dosingsystem; storing the added liquid nitrogen in the liquid nitrogen dosingsystem, at atmospheric pressure; dispensing the added liquid nitrogenfrom the liquid nitrogen dosing system into the container in acontrolled amount, during the step of mixing the ingredients, so as tofreeze the ingredients.
 17. The method of claim 16, further comprisingmeasuring viscosity of the ingredients and controlling the dispensing ofthe liquid nitrogen to the container responsive to the measuredviscosity.
 18. The method of claim 17, wherein the viscosity is measuredby monitoring a load on a motor configured to rotate the container or ona motor configured to move the one or more beaters.
 19. The method ofclaim 16, further comprising precooling an output pipe of the liquidnitrogen dosing system prior to dispensing the liquid nitrogen into thecontainer, using nitrogen gas from within the liquid nitrogen dosingsystem.
 20. The method of claim 16, wherein the level sensor produces asignal to activate the valve responsive to a control circuit.
 21. Themethod of claim 16, wherein the dispensing of the liquid nitrogen fromthe liquid nitrogen dosing system to the container is responsive to astored dosing algorithm comprising multiple releases of liquid nitrogen.22. The method of claim 21, wherein the dosing algorithm is responsiveto a viscosity measurement, a recipe or a batch size.
 23. The method ofclaim 16, further comprising rotating the container using a first motor,the beaters being turned to mix the ingredients using a second motor.24. The method of claim 16, further comprising measuring a temperatureand controlling the dispensing of liquid nitrogen from the liquidnitrogen dosing system into the container responsive to the measuredtemperature.